Water Quality Information

Last Updated December 23, 2013

Phase 1 Monitoring

Water quality monitoring needs have changed over time as the ash clean up progressed. Initially, ash removal proceeded as a time-critical CERCLA action. Work moved quickly to reduce the chances for downstream ash migration and upstream flooding in the event of a large rainstorm. Ash removed from the main Emory River channel and land areas east of Dike 2 was processed and transported off-site for disposal at an EPA-approved landfill. The purpose of water quality monitoring during this part of the CERCLA action (Phase 1) was to assess the safety of water supply sources, evaluate the potential impacts of the ash in the river, and determine the effectiveness of water quality protection measures used during ash removal and processing. Phase 1 monitoring continued through October 2010.

From the beginning, all TVA results have undergone a verification and validation process to ensure they meet the project’s rigorous data quality requirements. Reasons for failure of any results that do not pass those tests are investigated and corrected; if necessary, the original samples are re-analyzed.

Phase 1 monitoring results showed that high flows following heavy rainfall re-suspended ash and reduced water quality in the immediate vicinity of the spill for up to a few days, but that dredging of ash from the river (March 19, 2009-July 7, 2010), had minimal effects on water quality. Both TVA’s monitoring and mathematical analyses performed by the US Army Corps of Engineers showed that the amount of ash transported downstream by storms decreased as dredging removed more and more ash from the river.

Phase 2 Monitoring

The Emory River reopened to the public in May 2010, and the final ash disposal train left in December 2010, signifying time-critical work was essentially complete. Beginning in the summer of2010, operations shifted to a non-time-critical CERCLA action (Phase 2) involving stacking of excavated ash from the north and middle Swan Pond embayments into a reconstructed, reinforced dredge cell. Since most of that work is in the embayment, rather than the river, monitoring support for Phase 2 focuses on effects of rain events on water quality and the effectiveness of site water quality protection measures.

Runoff from the surrounding watershed naturally flows through Swan Pond Embayment and into the Emory River. A drainage channel, referred to as the Clean Water Ditch (CWD), was built to intercept runoff before it reaches ash in the embayment and directs the water around the ash and into the Emory River. Another drainage ditch was constructed to direct water that contacts ash in the embayment through a series of settling basins, where ash can settle out before water is discharged into the CWD and then to the Emory River. Sampling in these areas helps evaluate the effectiveness of this treatment to drain water from the site. Samples are collected monthly except at the CWD discharge point to the Emory River, which is sampled weekly, and after rainfall of one-half inch or more. Samples are tested primarily for arsenic, total suspended solids and several other ash-related materials.

Phase 3 Monitoring

A third phase involving the disposition of residual ash in the Emory, Clinch, and Tennessee Rivers also falls under CERCLA non-time-critical work. TVA, with EPA and TDEC oversight, is conducting investigations into possible ecological impacts of the residual ash as specified in the River System Sampling and Analysis Plan. Several of those investigations include water quality measurements. In addition, from October, 2010, through July, 2011, at the direction of EPA and TDEC, TVA monitored water quality during storm flows to evaluate ash re-suspension and downstream transport. Analysis of that data (See Appendix A in revised Surface Water Monitoring Plan) showed that storms no longer mobilize large amounts of ash. As a result, EPA and TDEC agreed to allow TVA to cease automated storm flow monitoring in the Emory and Clinch Rivers. Any additional SW monitoring associated with ecological or sediment sampling will be minimal and addressed (and reported) in association with the specific study.

Drinking Water

Kingston and Rockwood Water Treatment Plants

The Kingston and Rockwood water treatment plants sampled untreated and treated water (or drinking water) at daily, weekly, or monthly intervals immediately after the spill through December 2010. All drinking water results met applicable TDEC standards. Consequently, sampling has transitioned to normal pre-spill intervals at both water treatment plants. Plant personnel have the discretion to collect additional samples following heavy local rainfall or high water flows on the Emory River if they determine it is warranted.

Kingston Water Treatment Plant

Rockwood Water Treatment Plant

Private Wells & Springs

In the three months immediately after the ash release, TDEC sampled more than 100 private groundwater wells and springs within a four-mile radius of the site. TDEC continued to sample three sentinel wells quarterly for a time but has since discontinued monitoring these wells. TDEC has reported no violations of drinking water standards.